The present invention relates generally to flow cytometers and in particular to a flow cytometer using a multiphoton laser scanning microscope to provide interior fluorescence measurements of multicellular aggregates during flow processing.
The promise of regenerative medicine, using stem or other cells, requires a practical method of assessing multicellular aggregates as they are cultured to determine the viability, proliferative capacity and/or functional competence of the cultured population before implantation. The monitoring system should lend itself to monitoring large numbers of aggregates in an automated or semi automated fashion.
Flow cytometry is a known technique for monitoring individual cells in an automated fashion. In a typical cytometer, individual cells are dispersed in a liquid medium and passed through a channel that hydrodynamically focuses the cells in a line to pass an inspection region. In the inspection region, the cells may be electronically monitored, for example by light absorption, scattering, or fluorescence, and cataloged via high-speed computer. The monitored data may be used to operate a sorting mechanism that may sort the cells according to the monitored data into different channels for separation.
Multicellular aggregates can be disrupted under the sheer forces typically generated in a typical flow cytometer. In addition, conventional flow cytometry monitoring systems are not well adapted for the analysis of three-dimensional cellular structures.